Optimized path planning and scheduling strategies for connected and automated vehicles at single-lane roundabouts

by Lifeng Wang, Hu Liang, Yuxin Jian, Qiang Luo, Xiaoxiang Gong, Yiwei Zhang

This paper focuses on the cooperative driving challenges of connected and automated vehicles (CAVs) at single-lane roundabouts. First, a geometric path planning method is proposed for CAVs navigating a single-lane roundabout. Based on this method, a vehicle roundabout model is established. Four potential traffic scenarios for CAVs are established, and the optimal arrival times at conflict points are analyzed. By correlating the optimal arrival times at conflict points with the optimal entry times into the roundabout, the multi-vehicle coordination problem in complex intersections is simplified to a speed control issue during entry. Utilizing the principles of optimal control and Pontryagin minimization, two speed optimization strategies are proposed. Finally, MATLAB is employed for simulation analysis. The results indicate that the control strategy proposed in this paper enables the system to clearly identify potential conflicts between vehicles and implement an optimal control strategy, ensuring that vehicles can navigate the roundabout efficiently in terms of time and fuel without collisions. Additionally, the minimum time interval is established at 0.2 seconds to completely prevent vehicle collisions. In this study, the fusion problem involving two vehicles at a single conflict point is further expanded to encompass multiple vehicles at multiple conflict points. Thus, the efficient scheduling of multiple vehicles in single-lane roundabouts is realized.

Enhanced wound recovery after surgery care in patients with total knee arthroplasty: A meta‐analysis

Abstract

This study primarily focussed on the impact of Enhanced Recovery After Surgery (ERAS) care on wound healing and pain management in patients undergoing total knee arthroplasty (TKA). TKA is the critical surgical intervention aimed at improving the quality of life in patients with knee osteoarthritis. While this procedure has been effective in enhancing mobility and life quality, postoperative phase, particularly wound healing, remains significant concern. This research aimed to evaluate the effectiveness of ERAS care protocols in promoting wound healing and reducing postoperative wound pain. A comprehensive literature review was conducted to identify studies focusing on wound healing and pain management in TKA patients under ERAS care. The systematic search employed various terms related to TKA, wound healing and ERAS. During the screening process, data relevant to wound healing outcomes were prioritized for inclusion in the meta-analysis. Using the R package ‘meta’, meta-analysis was performed on a sample of 664 patients, divided into 349 in the intervention group (ERAS care) and 315 in the control. The results indicated significant enhancement in wound healing and reduction in postoperative wound pain among patients receiving ERAS care (risk ratio [RR] = 1.12, 95% confidence interval [CI]: 0.9152; 1.3929, p < 0.01). Additionally, pain score analysis across the studies revealed that the ERAS group consistently experienced less wound pain postoperatively compared with the control, with average of 0.1 point difference in pain scores indicating significantly less pain. Conclusively, our findings underscored the importance of implementing structured ERAS care protocols in TKA procedures. These protocols not only alleviated postoperative wound pain but also promoted effective wound healing, thereby potentially enhancing overall recovery and surgical outcomes for patients with knee osteoarthritis undergoing TKA.